Die polishing or lapping machine



NOV. 4, 1952 s HARDY 2,616,224-

DIE POLISHING 0R LAPPING MACHINE Filed April 8, 1949 3 Sheets-Sheet 2 I F/GZ' 63 64 o .5 912 32 35b 34b I I a WI 493 28b 4 27b a 343 h E if, Z 5a I 8 1223 21a /7b 0 l ml [2b 12a 27a 9 7/ 0 I 56 Z I Q MI I "I ll M a l \T 1 I Inventor Attorney Nov. 4, 1952 N. s. HARDY DIE POLISHING OR LAPPING MACHINE 3 Sheets-Sheet 3 Filed April 8, 1949 FI-G 51 IOa Ila 2 ttorney Patented Nov. 4, 1952 UNITED "STATES OFFICE NormanSamuel'Hardy, Rugby, England, assignpr 1:0. Kneller (Instruments -& 'Tools) Limited,

Rugby, England 9-Claims. a1

This invention ooncernsdiep'olishin (which expression includes lapping) -ma'c'hines of I the type comprising 4 a 'pair of spaced wire holders for .hold-ing a taut :wire betweenlthem, a rotary work 'h'ead for the 'reception 'of the i die with :the wire extending through its aperture, and 1 means for efiecti'ng relative reciprocationbetween the wire-holders and the "work head so that the 'wire iscaused tOrub to and fro through the die as the latter is rotated. Such ma'chines commonly used -for-' polishing the dies (made of diamond or other hard material such as tungsten-carbide) employed for wire'drawing and an object of the present invention is to effect A improvements on these machines.

"It will 'be-understood that as the'relative reciprocat-ions take place the die rubs on'acertain length ofthe wire which for the sake 'of convenience is referred to herein as the rubbing -zo'ne.

It is undesirable that this-rubbing actionshquld always take placeon the same length of wire and therefore the present invention provides "a die polishing machine of the type specified having'autom-aticmeans forefiectin-g a progressive and gra'dua1 adjustment first in one direction and -then in the reverse direction between the wire holders an'd'thework head insuch manner that the rulobing "'zone is gradually shifted along the "wire first in'one direction and then in the reverse direction. Forthis' purpose-the machine preferably comprises *a frame on which the two wire'hold'ersare mounted,-a' reciprocating driver, a driving connection 'between the driverand the frame, -'-an-d "means for gradually increasing and decreasing the effective length f the driving connection. -It will thus be appreciated that without any'alte'ration-in the-stroke of the frame the mean positionof the latter inrelation'to'the head is-gradually adjusted,ithereby producing a corresponding displacement of the rubbing zone.

The automatic means before mentioned may comprise an adjusting screw mechanism,'forward and reverse racking means for it, and changeover means-for changing the direction of the racking movement. In particular there I may be an adjusting screw, racking mechanism for rackingit in either direction, and change-over means for-determining the direction in which it is racked. This adjusting screw may form the driving connection aforesaid.

The invention also provides a die polishing machine of thetype-specified, having means for effecting relative adjustment between the wire and the work head in two mutually transverse directions each --substantia11y -normal to the length 0f the wire. This permits adjustment to be made: inone direction according to the re quired xternal 1 diameter of the die and adjustment to bemade inatransverse direction a-ccording to the diameter ofthe wire. Preferably the wire is (e; g. the wire holders are) adjustable in one direction and the head is adjustable in-a transverse direction.

The invention further. provides a die polishing machine of-the-type-specified,--having a standard or b'ody carrying on-each side-o=f=it a pair of-wire holders andth-e associ-ated work head, and having mechanism for effectin reciprocation between 'e'aohbpair of wire holders and the associated-head. This-mechanism may be;common to -both;parts' of the machine. The advantage of this construction-is that the machine may be built more chea'ply and" occupies less space'than two single machines while "furthermore -it-results in the various parts requi-rin adjustment being-'aocessibly located.

The iforegoing "and-other features of the' invention set out in the appended claims are incorporated in the die polis'hing-machineof thetype specified which will no-w be described as an example with reference to the accompanying drawin'g's'inwhioh #Figures 1 and 2 are .V perspec'tive views *of the machine, 'looking from the front and rear --respectively;

Figure-'35s 'a cros-s section, taken in avertical plane, showing the frame, the mec'hanism-for reciprocatin it, and the mechanism for: efiecting the progressiveaidjustment before mentioned;

Figure 4 is a cross Sec-tion, taken in a vertical plahejthrough on'e of thework heads;

Fi'gure 5 -is a s'ectionarelevati-on and Figure 61s a plan of aportion' df the mechanism for eiTecting thesaidprogressi've adjustment.

This-' machineis E a double machine, comprising astanda'rdjor body 1 marrying at' each-"sicle of ait-a work-head da, 2b respecti-ve1y and' beingequipped with -a single wertically recipr'ocatable irame '3 carrying-two pairs (viz. 4a; 5d,*and"4b,' 5b) ofwife holders, "eacnarr'anged*to co operate with- (meet the heads. The 'frame oin'prises 'a member' ti slidablyfniourited in'the vertical guides l 0- on the standard. 1 and ore-mama the top a'n'dtot'tom with'cro's'sbars I "and! respectively. Each "arm of each cross bar c-ar'ries a wire holder "that is capable of being adjusted along the length of the arm, "vizfin a direction hormal'to the length of the wire, the-latter being vertical. Alternatively each wire l'idlder is so constructed as to permit the wire to beshifted along the length of 3 the arm without the holder itself being shifted. A scale 9 is provided for the aforesaid adjustment of each wire.

The two work heads 2a, 2b are substantially identical and it is therefore only necessary to describe the work head 2a in detail, with particular reference to Fig. 4, it being pointed out that like parts in, or associated with, the two heads 2a, 2b have like reference numbers distinguished as regards the head 2a by the addition of reference a and as regards head 2b by the addition of reference I).

The head 2a comprises a chuck [a in which the die to be lapped or polished may be mounted and this chuck is itself rotatably mounted in a casing or body Ila and driven through belts l2a and I4 or other gearing from a driving motor [3 and a lay shaft E5. The head casing H a is carried by a bracket [to which is mounted on horizontal guides Ila formed on the associated side face of the standard I and extending from front to rear. The bracket Ilia together with its head 2a is therefore adjustable horizontally along the guides Ha in a direction which is normal to the length of the wire and-is transverse to the direction in which the wire is adjustable. Means IBa are provided for locking the bracket in the desired position of adjustment.

It is desirable that the machine should incorporate facilities for lapping dies having a conical aperture or having an aperture provided with a conical counter-sink, and dies having ne edge of the aperture formed with a radius. For the first purpose means are provided whereby each head may be so adjusted that its axis of rotation is inclined to the vertical, and for the second purpose each head is provided with means whereby as the head is rotated itsaxis of rotation may be repeatedly and slowly rocked into and out of the vertical.

These features are exemplified in head 2a. Its mounting bracket l6a incorporates a horizontal spindle 19a to the front end of which the head is attached. The attitude of the axis of the head may be set either by adjusting the head on the end'of thespindle ifiaor by adjusting the spindle rotationally within the bracket lBa. Conveniently there is a lug 20a protruding upwards from the head casing! la and provided with a slot 22a which is transfixed by the end of the spindle, the lug being gripped betweena collar 23a on the spindle and a nut24-aonthe end of the latter. It will be understood that if the head is set so that its axis is inclined to the vertical, the machineis thereby adapted to polish or lap a conical diehole or one having a conical counter: sink. The lug 20a is provided with an adjusting screw. 25a extending into the slot 22a to bear against the spindle 19a, so that the. height of the head may readily be adjusted. Attention is also directed to the clamping screw 2 la in bracket li which permits the spindle l9a to be clamped ineany desired, rotational position. Thereby the head 2a may be fixed with its axisatany desired angle to the wire, and/or (in conjunction-with the adjustment afforded by slot 2 2a, adjusting screw 25a, and clamping nut 24a) permits the head to be adjustedlaterally of the wire (with its axis either parallel with or disposed at an angle to the wire) and clamped in the adjusted position. t

In order that a radius at one end of the diehole may be polished or lapped the rear end of each spindle l9a, I9b is provided with a crank arm 260. or 26b which is connected by a connecting rod 21a or 27b to one arm of a rock lever28a or 28?) which is pivoted intermediate its ends (at 29a or 29b) and carries on the other arm a cam follower 30a or 301) engaging a rotatable cam 3| which is driven through suitable gearing (see 32 Figs. 1 and 2, and 33, Fig. 3) from the driving motor [3 of the machine. The cam followers 30a, 30b for the two heads engage the same cam 3! at substantially diametrical opposed locations under the influence of spring 34 and it will be appreciated that the arrangement is such that as the cam 3i rotates the rock levers 28a, 2822 are rocked and if the locations at which the connecting rods Zia, 27b are pivoted to them are offset from the axes about which the levers rock then the two spindles [9a, [9b are rocked to and fro and the two heads 2a, 2b are rocked so that their axes of rotation are slowly moved to and from the vertical.

Means are provided for adjusting the points. at which the connectingrods 27a, 211) are pivoted to the rock levers 28a, 281), into and out "of coincidence with the axes of said levers thus permitting the angle through which each headis rocked to be adjusted, it being understood that when the said points are coincident with the axes of the levers the heads are not rocked at all. For example each rock lever may comprise a bar which transfixes a block 34a or 34b to whichthe connecting rod 27a or 2122 is pivoted, the said block being adjustable along the bar and being clamped in its position or adjustment bya clamp: ing screw 35a or 35b.

The effective length of each connecting rod 21a, 21b is also adjustable, for which purpose the lower end of the rod may slidably transfix a socket 36a or 3th pivoted to the end of the associated crank arm 26a or 26b, the socket being provided with a screw 31a or 31b for clamping the rod in the desired position of adjustment. I

The frame 3 carrying the wire holders is reciprocated vertically by the following mechanism. The standard i carries a vertically slidable plunger 39 (Fig. 3) the top end of which is provided with a forwardly protruding arm 4!] in which a vertical lead screw 4! is rotatably mounted, the lower end of this lead screw screw ing through a nut 42 carried by the frame. The lower end of the plunger 39 is attached to a cross piece 43 having a horizontal cylindrical bore in which a cylindrical slider 44 is mounted, and this slider 44 is pierced with cross bore 45 into which a crank pin 46 protrudes through a slot 41 extending lengthwise of the cross member 43 The crank pin 46 is mounted on a crank shaft 48 (advantageously carrying the cam 3|) which is driven from the driving motor I3 through reduc:-.. tion gearing 33 and it will therefore be'under stood that as the crank pin 46 travels in its circular path the sliderll l travels with it'and alsoslides to and fro inside the cross member 43 with the result that the plunger-39 is raisedand lowered and the frame 3 is reciprocated.

'This reciprocation. of the frame causes the wires to be reciprocated vertically-s0 that they rub' on the internal peripheries of the dies'car ried by therotating workheads 2a, 2b. In order to adjust the rubbing zones theleadscrew'd-l is racked round first in one direction through a-predetermined number of motions andtheninthe reverse direction. Thereby the rubbing zones are gradually shifted first towards-one end of the wires and then towards the other end thereof. The step-by-step rotation of the screw in efiect adjusts the length of the connection that extends between the fra'me 3- and the reciprocating arm 4B'which drives it. ;It: is .producediby the following mechanism.

The top'endof the screw 4! carries a. ratchet wheel 59 with square teeth 56 on its upper surface. On the top of the standard there is pivoted at 5 a pendulous member 5| which carries two pivoted pawls 52, 53 that extend, from their pivcts, inwards towards one another and are both capable of engaging the ratchet wheel 59. The pendulous member 5! is movable between right and left hand positions which are determined by stops 55, 55, a spring detent 57 being provided for maintaining it in either position. When in the right hand position the left hand pawl .53 is operative and the right hand pawl 52 inoperative and when in the left hand position (Figs. 5 and 6) the right hand pawl 52 is operative and left hand pawl 53 inoperative. The pawls 52, 53 change over'as the pendulous member 5i moves from one position to another.

For holding either pawl inoperative'there is a bluff 53 freely mounted on the top end of screw 4| above the ratchet wheel 49. This bluff has a cut out as of sufficient size to permit one pawl only to engage the teeth 56 and is provided with stop pins 8B, 6! between which a pin 62 on the pendulous member 5i is received. Thus, when the pendulous member 51 swings to the left (Figs. 1 and 6) to bring the right hand pawl 52 into operation, the bluff 553 is moved in a clockwise direction, Fig. 6, to bring the cut out 59 under pawl 52 and to bring a plane part under pawl 53 so that the latter is prevented from engaging the teeth 59.

As the frame 3 rises the ratchet wheel it is brought into engagement with the operative pawl and the latter is swung up about its pivot 63 and t4. ihe arc of movement of the end of the pawl is such that in this swinging movement the ratchet wheel 39 is rotated through one tooth space. The pressure of the pawl tends to swing the pendulous member 51 away from the extreme position then occupied by it. This tendency is normally overcome by the spring detent 51 but, when the screw ll has been adjusted to a predetermined extent in either direction, limit stop mechanism prevents its further rotation in that direction. Since the ratchet Wheel 49 is thus prevented from further rotation the forces acting on the operative pawl now become sufficiently large to overcome the restraining influence of the detent 5?. The pendulous member 5| is therefore forced over to the other extreme position and in this movement the bluff 58 is shifted so that the previously operative pawl is lifted to its inoperative position and the other pawl is lowered to its operative position. This other pawl thereupon proceeds to rack the screw in the reverse direction each time the frame reaches the top of its stroke.

The limit stop mechanism may consist of upper and lower stop pins 55, 66 protruding from the frame 3 and a plate or other member 6? fixed on the screw ill and having two diametricallyopposed tongues 68, 59 one of which is directed upwards and the other downwards. When rotation of the screw il carries the nut t2 and frame 3 downwards, the upturned tongue 68 eventually fouls the top stop pin 85 and prevents further rotation of the screw; upon rotation of the screw in the reverse direction the downturned tongue 69 eventually fouls the lower pin 56 and prevents further rotation in said reverse direction.

I claim:

1. A die polishing machine of the type coming 6. prising, a. pair. of spaced wire holders for-.holding a tent :wire between :them, a -rotary workv .head fortlie receptionof the vdie with: the wire extending through its aperture,.and means. for efiecting relative reciprocation between the wire holders and the work head so that airubbing zone of the wire is caused to rubto and fro through the die as the latter is'rotated, automatic means mounted on'the machine and acting while the machine is in operation for effecting a progressive and gradual adjustment. first in .one .direction and then in the .reversedirection between the wire holders and the work ..head and -for thereby gradually shifting the rubbingzone'along .the wire first in one direction-and theninlthe :therefor, and change-over means for changing the direction of the racking movementafter a predetermined number of racks in either direction.

3. A machine according to claim 1, comprising a frame on which the two wire holders are mounted, a machine body having guide means on which the frame is reciprocatably mounted, a reciprocating driver, guide means on the machine bodyin which means the driver is reciprocatably mounted, an adjustable driving connection extending between the driverand the frame, and means for gradually changing the effective length of the driving connection, first in an increasing and then in a decreasing direction upona predetermined cumulative change in effective length,

and for thereby gradually shifting the frame to and fro in relation to the driver.

4. A machine according to claim 3, wherein the automatic adjusting means comprises an adjustscrew forming the driving connection between the driver and the frame, forward and reverse racking means therefor, and change-over means for changing the direction of the racking movement after a predetermined number of racks in either direction.

5. A die polishing machine, comprising a standard, a frame mounted thereon for reciprocation, two pairs of spaced wire holders on the frame each pair for holding a taut wire extending between the two holders in the direction of reciprocation, two rotary work heads intermediate the wire holders, one for each wire, each adapted for the reception of an apertured die with the wire extending through the die aperture, means for mounting each work head on the standard for adjustment in a direction normal to the direction of reciprocation, means for rotating each die in its work head, means mounting each work head for pivotal movement about an axis substantially normal to the axis of rotation of its die and to the length of the associated wire, means for oscillating the two head continuously about their axes of pivotal movement, means for adjusting the angular amplitude of such oscillation, means for reciprocating the frame on the standard and for thereby causing a rubbing zone of each wire to rub to and fro through its die as the latter is rotated, and automatic means for effecting a progressive adjustment of the reciprocating frame along the line of its reciprocation on the standard, first in one direction and then in the reverse direction, and for thereby correspondingly progressively shifting the rubbing zones along the wires.

6. In a die polishing machine of the type comprising a standard, a frame reciprocatably mounted thereon, a Work head on the standard for carrying a rotating die, means for rotating the die, a pair of spaced wire holders on the frame for holding between them a taut wire extending through a hole in the die, and means for reciprocating the frame on the standard so that a rubbing zone on the wire rubs to and fro through the rotating die, the combination of a driver for the frame, means mounting the driver on the standard, lead screw mechanism, connecting the driver to the frame, for reciprocating the latter, and for adjusting the rubbing zone along the wire, forward and reverse racking mechanism for racking the lead screw mechanism and for thereby adjusting said zone, and means for changing over the direction of racking upon a predetermined extent of adjustment in either direction being achieved while the machine is in operation.

7. A machine according to claim 6, wherein the last said means comprises limit stop mechanism.

8. A machine according to claim 6, comprising a ratchet wheel on the frame and connected to the screw mechanism to rack the latter, a pawl carrier on the standard movable between forward and reverse racking positions, a forward racking pawl and a reverse racking pawl mounted on the pawl carrier for engagement, when operative, by the ratchet wheel at each reciprocation of the frame and for thereby racking the wheel and by reaction urging the pawl carrier to change over between its two positons, a bluff movable between a position in which it bluffs the forward pawl and a position in which it bluffs the reverse pawl, a connection between the pawl carrier and the bluff for causing the latter to change over between its two positions when the pawl carrier changes over, limit stop mechanism for preventing rotation of the lead screw mechanism in one direction upon a predetermined rotation in that direction having been achieved and in the opposite direction upon a predetermined rotation in said opposite direction having been achieved, and

a spring-loaded detent normally preventing change-over of the pawl carrier but yieldable under the pawl reaction upon rotation of the lead screw mechanism being stopped by the limit stop mechanism.

9. In a die polishing machine of the type com prising a standard, a frame reciprocatably mounted therein, a work head on the standard for carrying a rotating die, means for rotating the die, a pair of spaced wire holders on the frame for holding between them a taut wire extending through a hole in the die, and means for reciprocating the frame on the standard so that a rubbing zone on the wire rubs to and fro through the rotating die, the combination of a driver for the frame, means mounting the driver on the standard, operating connections between the driver and the frame, automatic means for adjusting said connections to gradually shift the frame in relation to the driver, first in one direction and then in the opposite direction, and for thereby gradually shifting the rubbing zone to and fro along the wire, means mounting the work head on the standard for pivotal movement about an axis normal to the length of the wire and incorporating releasable means for securing the work head at any required pivotal angle, and mechanism for oscillating the work head about said axis concurrently with rotation of the die in the head, which mechanism includes adjustable means for pre-setting the angle of oscillation.

NORMAN SAMUEL HARDY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 925,233 Schmidmer June 15, 1909 1,714,869 Haddow May 28, 1929 1,826,347 Haddow Oct. 6, 1931 1,885,178 Bsteh Nov. 1, 1932 2,470,331 Bieberich May 17, 1949 

